Aluminoxane-based Activator Chemistry

塑料是一种用途广泛的材料，用于各种各样的产品。聚烯烃是一类由烯烃单体（含有C=C双键的简单分子）聚合形成长链烃（具有C-C单键主链）制成的塑料。它们在催化剂的帮助下在世界范围内大量生产。催化剂加速化学反应而自身不受影响，并且在聚烯烃的制备中，使用含有过渡金属的催化剂。然而，催化剂需要活化才能够帮助所需的转化，并且该活化步骤的关键工业方法是使用大量过量的称为甲基铝氧烷（MAO）的高反应性化合物。使用的过量是如此之高（1000- 10，000当量），以至于MAO占催化体系成本的很大比例。过量使用可能是由于MAO的活化组分仅作为整体的一小部分存在，但MAO的复杂性使得其在超过25年的时间里一直拒绝明确表征。

Plastics are versatile materials used in an enormous array of products. Polyolefins are one class of plastics made from polymerizing olefin monomers (simple molecules containing a C=C double bond) to form a long chain hydrocarbon (with a backbone of C-C single bonds). They are made in huge quantity worldwide with the help of catalysts. Catalysts speed chemical reactions without themselves being affected, and in the preparation of polyolefins, catalysts containing transition metals are used. However, the catalyst requires activation before it is able to assist the desired transformation, and the key industrial approach to this activation step is to use a large excess of a highly reactive compound called methylaluminoxane (MAO). The excess used is so high (1000-10,000 equivalents) that MAO represents a significant proportion of the cost of the catalytic system. The excess used is probably due to the fact that the activating component(s) of MAO are present only as a small fraction of the whole, but the complexity of MAO is such that it has resisted unambiguous characterization for over 25 years.